Free wheel hub mechanism

ABSTRACT

A free wheel hub mechanism for a vehicle including an axle shaft for the front wheels adapted for selectively receiving a driving force from a vehicle engine, a cam member rotatable with the axle shaft, a non-drive member operatively connected to the front wheels and frictional means disposed between the cam member and the non-drive member, the frictional means being automatically and frictionally engaged with the non-drive member by the cam member when driving force is transmitted to the axle shaft and being automatically disengaged from the non-drive member when the driving force is interrupted, whereby the operator automatically has either a rear two wheel drive or a four wheel drive, and the front driving system is not rotated while the rear two wheel drive is effective.

[451 Oct. 16, 1973 F "R E E WITETEIT Inventor: Tooru Kagata, Toyota,Japan Aisin Seiki Kabushiki Kaisha, Kariya City, Aichi Pref, JapanFiled: May 25, 1972 Appl. No.: 256,764

Assignee:

[30] Foreign Application Priority Data May 25, 1971 Japan 46/035697References Cited UNITED STATES PATENTS 7/1966 Kramm 192/35 X 11/1942Bialy 192/75 X 3/1926 Barnes 192/43 X 4/1972 Gruchmann 192/35 2,194,2283/1940 Jex 192/75 Primary Examiner-Allan D. Herrmann Attorney-Norman F.Oblon et al.

[5 7] ABSTRACT A free wheel hub mechanism for a vehicle including anaxle shaft for the front wheels adapted for selectively receiving adriving force from a vehicle engine, a cam member rotatable with theaxle shaft, a nondrive member operatively connected to the front wheelsand frictional means disposed between the cam member and the non-drivemember, the frictional means being automatically and frictionallyengaged with the non-drive member by the cam member when driving forceis transmitted to the axle shaft and being automatically disengaged fromthe non-drive member when the driving force is interrupted, whereby theoperator automatically has either a rear two wheel drive or a four wheeldrive, and the front driving system is not rotated while the rear twowheel drive is effective.

5 Claims, 3 Drawing Figures PATENTEU OCT 18 I975 SHEET 1 BF 2 1 FREEWHEEL HUB MECHAMISM BACKGROUND OF THE INVENTION This invention relatesto free wheel hub mechanisms for vehicles, and more particularly relatesto free wheel hub mechanisms of the kind in which the driving connectionbetween the engine and the front wheels is established or interruptedaccording to the driving conditions and the requirement for either twoor four wheel drive.

conventionally, when an operator adjusts a transfer means connected tothe engine to obtain two wheel drive, for example, when the vehicle isrunning under lifetime of the arrangement, especially of a plurality ofbearings provided therein, will be decreased. In addition, noises willbe generated at the mechanical connecting parts in the front wheeldriving system and the amount of consumption of fuel will be furtherincreased because the front wheel driving system is raced.

On the other hand, it has been proposed that conventional free wheel hubmechanisms be provided with manual locking means allowing the frontwheels to rotate regardless of the rotation of the front axle shaft.Accordingly, when rear wheel drive only is established by manualadjustment of the transfer means, the front wheel driving system of thismechanism will not be raced. However, it will be noted that four wheeldrive will still only be established when the transfer means is manuallyadjusted into its four wheel drive position. For the establishment offour wheel drive in this case, besides the adjustment of the transfermeans, the operator also must adjust the manual locking means to thelocking position in which the engine is drivingly connected to the frontwheels. In addition, when the operator adjusts the locking means, hemust get off the vehicle because the wheel hub mechanism is providedbetween the axle shaft and the wheel. Obviously, hev must also get offthe vehicle in order to subsequently readjust the locking means back toits rear two wheel drive state from its four wheel drive condition.

SUMMARY OF THE INVENTION vide an improved wheel hub mechanism whereinthe driving connection between the engine and the front wheels isautomatically established when the driving force from the engine istransmitted to the driving system thereof and the driving connection isautomatically interrupted when the driving force is interrupted.

It is a still further object of the present invention to provide animproved wheel hub mechanism wherein the driving system will not berotated when a driving force is not transmitted thereto.

The foregoing objects are achieved according to the present inventionthrough the provision of a free wheel hub mechanism featuring an axleshaft for the front wheels adapted to selectively receive a drivingforce from the vehicle engine and having a cam member rotatabletherewith, a non-drive member connected to the front wheels andfrictional means disposed between the cam member and non-drive memberbeing automatically frictionally engageable with the non-drive memberupon rotation of the cam member when the driving force is transmitted tothe axle shaft and disengaged when the driving force is interrupted.Thus, wheel rotation will not cause rotation of the axle shaft in twowheel drive operation.

BRIEF DESCRIPTION OF THE DRAWINGS These and further objects, featuresand attendant advantages of the present invention will be more fullyappreciated as the same becomes better understood from the followingdetailed description when considered in connection with the accompanyingdrawings wherein like reference characters designate like orcorresponding parts throughout the several views, and in which:

FIG. 1 is a cross-sectional view of a free wheel hub mechanism accordingto the present invention;

FIG. 2 is a sectional view taken along the line A-O-A of FIG. 1; and

FIG. 3 is a sectional view taken long line 8-8 of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings, thereference numeral 10 denotes an axle shaft for the front or rear wheels,not shown, adapted for receiving a driving force from a vehicle engineupon the manual adjustment of a transfer means, not shown. The axleshaft 10 has a plurality of splines 10a formed on the outer peripherythereof. A cam or drive member generally designated by reference numeral11 is formed with a plurality of splines 11a which are engaged with thesplines 10a of the axle shaft 10 so that the cam member 11 is rotatedwith the axle shaft 10 when the driving force is transmitted to theshaft 10. The cam member 11 comprises an annular portion 11b whichsupports rotatably at the outer periphery thereof a non-drive member orcase 12 and a recessed inner portion having the outer periphery thereofformed into two diametrically opposed planar surfaces to provide camportions 11d and He. A case cover 13 is secured by bolts 14 to the case12 which is in turn secured to a flange 15 by the same bolts 14. Theflange 15 is operatively connected to the wheel, whereby the flange l5and the case 12 are rotated with the wheel.

A pair of frictional members or pieces 16a and 16b each being of arcuateor half-circle configuration, is disposed between an inside surface 12aof the case 12 and the recessed inner portion 110 of the cam member 11.Each of the pieces 16a and 16b is formed with cam portions and 16d atits ends, or substantially being diametrically opposed, which arecontacted with the cam portions 11d and lle, respectively, of therecessed portion 110 upon rotation of the cam member 11. A gap 17 isprovided between the inside surface 12a of the case 12 and the outsideperipheral surface 16e of each piece. A pair of pins 18a and 18b arepivotally mounted on the two pieces 16a and 16b, respectively, wherebythe pieces 16a and 16b are expanded radially and outwardly around thepins 18a and 18b under the influence of a clutch assembly generallydesignated by the reference numeral 26 when the cam member 11 isrotated, as will be described in further detail hereinafter. A pair ofsprings 19a and 19b are provided, being respectively disposed betweenthe respective opposite end portions of the pieces 16a and 16b, to biasthe pieces 16a and 16b into the neutral positions shown in FIG. 2.

A connecting means between the clutch assembly and the pieces 16a and16b is provided by pins 18a and 18b which are formed integrally with acage 20 having a plurality of annularly oriented projecting portions atthe inner end thereof, being shown as six in number. The six projectingportions of the cage 20 are fitted and supported in an inside peripheryof an outer race 21 which is pressed against a stationary portion 22 ofthe vehicle and is secured to a knuckle 23 by a nut 24. A washer 25prevents the nut 24 from rotating. The clutch assembly 26 includes theouter race 21, a plurality of bush members 28 disposed within the outerrace 21 and fitted between the projecting portions of the cage 20, and aspring band 27 disposed between the bush members 28 and the nut 24. Thebushes 28 are always biased radially outwardly by the biasing force ofthe spring band 27, thereby being pressed against the outer race 21.

A bearing 29 is provided between the flange 15 and the stationaryportion 22. A snap ring 30 is fitted to the shaft 10 for preventingleftward movement of the cam member 11, as viewed in FIG. 2, and a snapring 31 is fitted to the cam member 11 for preventing leftward movementof the case 12, also as viewed in FIG. 2.

In operation, assuming that the front wheel drive system is connected tothe engine by manual adjustment of the transfer means, the axle shaft 10receives the driving force from the engine and is rotated thereby andthe cam member 11 splined to the axle shaft 10 is rotated therewith.Assuming that the cam member 11 is rotated in the direction of the arrowC, shown in FIG. 1, the cam portions 11d and 1 1e of the recessedportion 110 engage, respectively, with the cam portions 16c and 16d ofthe pieces 16a and 16b, thereby causing the pieces 16a and 16b to expandradially outwardly. Thus, the pieces 16a and 16b are rotated in thedirections of the arrows D, respectively. At this time, the clutchassembly 26 is in a state of operation by the spring band 27 so that thepivot pins 18a and 18b act as fulcrums against the rotation of thepieces 16a and 16b. Accordingly, the outer peripheries of the pieces 16aand 16b are brought into pressure contact with the inside surface 12a ofthe case 12 so as to rotate the case 12. By this pressure contact, thepieces 16a and 16b receive the torque or the resistance from the insidesurface 12a in the direction of the arrow E, and, therefore, the pieces16a and 16b are permitted to further rotate. Namely, a servo effect willbe produced at this time. As is clear from hereinbefore, the drivingforce transmitted from the engine drives the wheels through the axleshaft 10, the cam member 11, pieces 16a and 16b and 6 the case 12. Atthis time, all the parts are rotated as a unit as though they wereintegrally formed as one body,

but the bushes 28 are allowed to slide with respect to the outer race21.

Next, assuming that the driving force to the front driving system isinterrupted by manual adjustment of 5 the transfer means, the pair ofsprings 19a and 19b causes the pieces 16a and 16b to move into theirneutral positions with respect to the shaft 10. Upon rotation of thewheels, the case 12 is rotated with the wheels through the flange 15.However, the pieces 16a and 16b are then sliding with respect to theinside surface 12a of the case 12. That is to say, the wheels will berotated without causing rotation of the axle shaft 10. Thus the shaft 10is not rotated unless the driving force is transmitted thereto.

Various other modifications and variations of the present invention areobviously possible in light of the above teachings. It is to beunderstood, therefore, that within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

Accordingly, what is claimed as new and desired to be secured by letterspatent of the United States is:

1. A free wheel hub mechanism for a vehicle characterized by an axleshaft adapted to receive a driving force from an engine of the vehicle,comprising:

a drive member connected to said axle'shaft for rotation thereby andbeing formed with diametrically opposed parallel planar cam portions onthe outer peripheral surface thereof;

a non-drive member having an inside surface of substantially cylindricalconfiguration coaxial with said axle shaft and said drive member andopera tively connected to wheels of said vehicle so as to rotatetherewith; and

35 first and second frictional pieces of semi-circular configurationbeing disposed between said drive member and said non-drive member, eachof said frictional pieces having opposing parallel planar cam portionson the inner surface thereof adjacent the diametrically opposed endsthereof being engageable with said cam portions of said drive memberwhen said axle shaft receives said driving force, whereby the outerperipheral surfaces of said frictional pieces are automatically andfrictionally engaged with said non-drive member by said drive memberwhen said driving force is transmitted to said axle shaft and areautomatically disengaged from said non-drive member when said drivingforce to said axle shaft is interrupted.

2. A free wheel hub mechanism as claimed in claim 1, wherein springmeans are inserted between said first and second pieces for biasing saidfirst and second pieces into a neutral'position.

3. A free wheel hub mechanism asclaimed in claim 1, further comprising:

a clutch assembly disposed between said axle shaft and said non-drivemember; and

a connecting means for connecting said first and second pieces to saidclutch assembly.

4. A free wheel hub mechanism as claimed in claim 3, wherein saidconnecting means comprises:

pins fitted, respectively, in said first and second pieces; and

5 a cage integrally formed with said pins and operatively connected tosaid clutch assembly. 5. A free wheel hub mechanism as claimed in claim4, wherein said clutch assembly comprises:

rotated around said connecting means when said frictional piecesreceives said driving force and said bush means are slidable in saidouter race when a driving connection between said drive member and saidnon-drive member is established.

1. A free wheel hub mechanism for a vehicle characterized by an axleshaft adapted to receive a driving force from an engine of the vehicle,comprising: a drive member connected to said axle shaft for rotationthereby and being formed with diametrically opposed parallel planar camportions on the outer peripheral surface thereof; a non-drive memberhaving an inside surface of substantially cylindrical configurationcoaxial with said axle shaft and said drive member and operativelyconnected to wheels of said vehicle so as to rotate therewith; and firstand second frictional pieces of semi-circular configuration beingdisposed between said drive member and said non-drive member, each ofsaid frictional pieces having opposing parallel planar cam portions onthe inner surface thereof adjacent the diametrically opposed endsthereof being engageable with said cam portions of said drive memberwhen said axle shaft receives said driving force, whereby the outerperipheral surfaces of said frictional pieces are automatically andfrictionally engaged with said non-drive member by said drive memberwhen said driving force is transmitted to said axle shaft and areautomatically disengaged from said non-drive member when said drivingforce to said axle shaft is interrupted.
 2. A free wheel hub mechanismas claimed in claim 1, wherein spring means are inserted between saidfirst and second pieces for biasing said first and second pieces into aneutral position.
 3. A free wheel hub mechanism as claimed in claim 1,further comprising: a clutch assembly disposed between said axle shaftand said non-drive member; and a connecting means for connecting saidfirst and second pieces to said clutch assembly.
 4. A free wheel hubmechanism as claimed in claim 3, wherein said connecting meanscomprises: pins fitted, respectively, in said first and second pieces;and a cage integrally formed with said pins and operatively connected tosaid clutch assembly.
 5. A free wheel hub mechanism as claimed in claim4, wherein said clutch assembly comprises: an outer race secured to astationary portion of the vehicle; a plurality of bush means mounted insaid outer race; and resilient means for biasing said bush means towardsaid outer race, said cage being inserted between said bush meanswhereby said frictional means is rotated around said connecting meanswhen said frictional pieces receives said driving force and said bushmeans are slidable in said outer race when a driving connection betweensaid drive member and said non-drive member is established.